Impedance-Domain Decoupled Single-Architecture Multimodal Strain Sensor Array for Full-Field Strain Mapping

Multimodal strain sensors integrating diverse transduction mechanisms expand sensing dimensionality. However, most multimodal devices rely on complex integrated architectures to suppress crosstalk and lack intrinsic sensing pathways for capturing strain dynamics. Here, we present a highly simplified multimodal sensor based on a single sandwich-type piezoelectric architecture, where a microcrack-based piezoresistive layer simultaneously serves as the piezoelectric electrode, enabling intrinsically decoupled sensing within a shared electrical channel via impedance-domain separation. Notably, the piezoelectric output directly reflects strain rate, complementing the piezoresistive readout of strain magnitude to achieve integrated dynamic-static strain sensing. Scalable and low-cost ultrasonic spray coating is further developed to fabricate large-area arrays (>10 cm × 10 cm) with uniform morphology and reliable performance. Owing to PVP-regulated ink composition, the piezoresistive layer exhibits an ultrawide linear strain range of 0.001%-45% and a dynamic response up to 700 Hz. Integrated with multichannel acquisition electronics, the platform enables spatiotemporal mapping of micron-scale deformations and strain trajectories, facilitating more reliable identification of failure sites under vibrational excitations and establishing a robust framework for comprehensive, high-fidelity structural health assessment.